Total Solar Eclipse!

Enchanted Learning Travels to Oregon

The Great American Eclipse

The solar eclipse of August 21, 2017, has been dubbed the Great American Eclipse, since totality could be seen coast-to-coast across the US, in a band about 65 miles wide going from Oregon to South Carolina (weather permitting, of course). This was the first total solar eclipse visible anywhere in the US mainland since 1979.

Click on a photo to see a larger version of it, and then click again for an even higher resolution image.

Towards Totality

By the time an hour had passed after first contact, only a small crescent of the Sun was visible. The crescent kept getting smaller and smaller, until only a tiny sliver and then just a wisp were left.

Finally, the Moon covered the entire disk of the Sun — totality! This was what all of us there were waiting for. The corona around the Sun appeared; it’s too faint to be seen when even a little bit of the Sun’s disk is visible. You can see the 10 minutes leading up to totality in the photo.

The sky was dark, but not black like a night sky (it looks black in the photos because of the solar filter and because the camera can’t distinguish the wide range of brightnesses that the human eye can).

Totality was only 1 minute 43 seconds where we were in Oregon; it went by very fast!

Observers closer to the eclipse path’s center line and those farther east had longer periods of totality; the maximum was 2 minutes 40 seconds near Hopkinsville, Kentucky.

The Sun’s Corona

This picture shows what the Sun looks like to the naked eye during totality. It’s black where you would expect the disk of Sun to be, and surrounding that is the now-visible corona, the Sun’s outer layer.

The corona is faint and much less dense than the rest of the Sun, but its temperature is very high, much hotter than the photosphere (the part of the Sun we usually see).

The View Through Eclipse Glasses

Here you can see what the Sun looked like through eclipse glasses. This one image was taken near Seattle, a few minutes after the maximum eclipse. (The eclipse was just a partial eclipse there, since Seattle was outside the band of totality.) Thanks to Danny Col-Spector for this photo!

Except for the very short period of actual totality, people who want to look directly at the Sun during a solar eclipse need to wear eclipse glasses or similar protection to prevent possible permanent damage to their eyes. Likewise, a camera lens needs a solar filter on it; the solar filter blocks most of the light so that the camera sensor and mechanism won’t burn out from the focused rays of the sun.

The eclipse glasses worked remarkably well, and showed a nice clear image, although too small to see the details that a telescope can unveil.

A Montage of the Entire Eclipse

That we can see solar eclipses at all depends on a remarkable coincidence: the Sun is about 400 times as far from us as the Moon is, and the Sun’s diameter is also about 400 times as big as the Moon’s diameter. So the disks of the Sun and the Moon look about the same size in our sky.

When everything happens to be positioned exactly right, the Moon can block our view of the entire disk of the Sun — a total solar eclipse! (If the Moon covers part but not all of the Sun’s disk, that’s a partial solar eclipse.)